Field of the Invention
Various aspects of the present invention relate to a vehicular dust sensor. More particularly, to a vehicular dust sensor capable of preventing deterioration of sensor performance or malfunction thereof due to deposition of dust in a case, or lens contamination and disturbance light introduced from the outside, and of resolving output abnormality from a light emitting diode and the resultant deterioration of sensor performance.
Description of Related Art
In general, optical sensors are widely used as dust sensors to measure the amount and concentration of fine dust contained in air, and particularly there is known a light scattering method of detecting the amount of light scattered through dust in air.
Such a light scattering type dust sensor includes a light source module having a light emitting element such a Light Emitting Diode (LED), a light receiving module having a light receiving element such as a Photo Diode (PD), and a lens for collecting light scattered by dust in air.
The light source part, the light receiving part, and the lens are installed in a case of the dust sensor. In this case, the case has an inlet port for introducing air which may contain dust.
When the LED of the dust sensor irradiates an illumination region in the case with light, the light is scattered by dust in air, i.e. dust particles, introduced into the case. In this case, the intensity (or amount) of the scattered light is proportional to the concentration of the dust particles in the air.
Accordingly, the dust sensor collects the light scattered by the dust particles in the air using the lens, and receives the collected light using the PD to output electric signals corresponding to the dust concentration.
However, the performance of the conventional dust sensor may easily deteriorate due to the deposition of dust in the case.
Particularly, the sensor may malfunction due to the contamination of the condensing lens therein, and the amount of light from the LED may be reduced due to the continuous use of the sensor and the sensitivity of the sensor may therefore deteriorate.
In addition, visible light or ultraviolet light may be easily introduced into the case through the air inlet port therein, and the light introduced from the outside acts as disturbance light which is a major cause of the malfunction of the sensor.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.